The processing of various flesh products, including meat and fish, involves the injection of mixtures and solutions, such as salt brine, and pickle for preserving, flavouring and curing such products. Typical such products include hams, picnics, bacon, shoulders, briskets, and any other products which may be injected with liquids from time to time. Such products may be pork, beef, poultry, or, for example, fish products, which are being further processed after dressing, cleaning, and chilling. All such injectable products are termed herein as "meat" whether the same includes any type of meat or poultry or fish.
The process of injection involves the insertion of a plurality of elongated injection needles into a meat section, after which the liquid is pumped into the meat. It is well known that this process leaves markings in the meat if the diameter of the needles is large and their spacing and orientation is regular, and when the meats are sliced for consumption, these markings appear as visible blemishes.
It is also known in the meat processing industry that in order to make use of the trim portions of lean meat, such trim portions may be finely ground and emulsified with a liquid. The emulsion is then used for making sausage products such as hot dogs, bologna, weiners, frankfurters, and the like.
In an attempt to alleviate the problem of markings and blemishes in meat sections resulting from the pickle or brine injecting process, it has been proposed to make a mixture of such a meat emulsion, similar to that used in sausage products, with a pickle or brine, and to inject this mixture into the meat sections. This proposal has not been entirely successful, and injection marks and blemishes are still visible.
Meat emulsions are in the form of a smooth cream in texture, in which the meat particles are so fine that it is impossible to distinguish them. By definition, the fine meat particles form a continuous phase in this mixture encapsulating the fat and moisture in the matrix of soluble protein derived from the meat. When injected into meat sections, i.e., muscle meat, the emulsion will still have the texture and appearance of a paste, and is easily detected with the naked eye when the product is sliced for consumption, so that the problem of blemishes is still present.
It has now been established that if, in place of the meat emulsion, a mass of finely divided meat pieces (i.e., less than 2.0 mm in length) is suspended in the pickle or brine where the aqueous phase is continuous, and the meat particles are held in suspension within this aqueous phase, this suspension can be injected into the meat sections in accordance with the process and apparatus disclosed herein. When such meat sections are so injected, and processed for consumption and sliced, needle marks or blemishes are no longer visible, and cannot be discerned by the naked eye. Consequently they do not impair the appearance of the meat when it is consumed.
An additional benefit of this process lies in the fact that, while the injection of brine or pickle mixtures assists in the curing of the meat sections, and the flavouring of the meat sections, it essentially "dilutes" the actual weight of the meat section. In other words, while a meat section weighing, for example 1000 grams, without injection of brine or pickle, and represents to the consumer as a buyer at that stage 1000 grams of meat, a section of 1000 grams to which, for example 300 grams (i.e., 30%) of brine or pickle mixture has been injected, has a total weight of 1300 grams, but still represents to the processor purchased meat of only 1000 grams. Consequently, when the consumer purchases a given quantity of meat products processed with pickle or brine, at for example an injection rate of 30%, the consumer is in fact receiving original muscle meat of approximately 1000/1300.times.100=76.9% of the total weight purchased.
This factor is, of course, well understood in the industry, and in fact is carefully regulated by industry practice and government regulations. When, however, such meat sections are injected with finely divided meat pieces, suspended in the pickle or brine mixture, then the consumer is in fact receiving muscle meat, additional to that contained in the actual meat section which is injected. Thus the consumer is in effect receiving more value for money, in addition to receiving a product which is more visually appealing when sliced and consumed, than a product which is injected simply with the usual liquid mixture of pickle or brine.
This factor is advantageous to the processor for two reasons. In the first place, the public will perceive the product as being more desirable than a product injected in the conventional way with liquid brine, and will thus tend to purchase the improved product rather than the unimproved product. In addition, however, there is a further advantage to the processor, namely, that under the old practice where the meat trimmings were ground and emulsified for making sausage products, they resulted in a lower price being obtained for the product. However, by the use of the invention, where such meat trimmings are finely divided and are then incorporated in an injected product, then they will be fetching a somewhat higher price, and consequently the process will have economic value to the processor beyond the factor of simply making the product more appealing. Such a suspension is defined herein as a "cold milled particle reduction suspension", and in such suspension the particles are less than 2.00 mm in any dimension.
Attempts to carry out this process using conventional injection needles and pumps, designed for injecting conventional liquid pickle or brine mixtures have been unsatisfactory. Conventional injection equipment consists simply of a plurality of needles mounted on a moveable framework, which could be operated automatically to repeatedly plunge the needles into the meat sections, while the meat sections were moved progressively in step-wise fashion past the needles. In addition, such conventional equipment included a tank for holding the brine, and a pump. However, it is found that when using this relatively simple equipment to inject a suspension of meat pieces, the nature of the suspension of meat pieces undergoes an irreversible change due to temperature rise. As a result, the suspension turns into a jelly-like mass, in which condition it is impossible to handle, and it is impossible to inject it, into meat sections.
In addition, conventional injection needles employ a design in which the end of the needle is pointed, for ease of insertion, and in which a central passageway down the interior of the needle, terminates in an opening adjacent one side of the needle (i.e., the needle discharge port is radial drilled).
It is found that these needles are unsuitable for the injection process, when operating with a suspension of meat pieces.
A further problem was encountered using conventional equipment in that the suspension of meat pieces was found to be unsuitable for pumping through conventional equipment, and modifications were required before the suspension could be pumped satisfactorily at a constant pressure.
A further feature arising from the nature of the suspension was found to arise from the fact that the suspension has a much greater resistance to flow along a conduit than does a liquid pickle or brine, and the conduits, especially the smaller diameter conduits leading to the injection needle, on conventional equipment were found to create too much resistance to flow. In addition, conventional equipment would become plugged with such suspension, and had to be repeatedly cleared out to ensure free flow.
It is also found in practice that there is some degree of wastage in the injection of the suspension, which will then cause loss to the process. Using conventional equipment this wastage could not be recovered.
It has also been established that even with the equipment designed for optimum performance, the steps of injection were preferably carried out in a certain manner and at a certain temperature range in order to achieve maximum efficiency.